In addition, many drugs are known to affect thyroid hormone pharmacokinetics and metabolism by altering absorption, synthesis, secretion, protein binding, and/or target tissue response, and may also alter the therapeutic response to thyroid hormone preparations such as levothyroxine. In addition, thyroid hormones and thyroid status may have varied effects on the pharmacokinetics and actions of other drugs. A list of drug-thyroidal axis interactions is provided in the prescribing information for marketed agents such as Synthroid® (levothyroxine sodium tablets, USP), Abbott Laboratories and Cytomel® (liothyronine sodium tablets), King Pharmaceuticals, Inc.